In Figure 1.4, we see some examples of what alternative alkyl substituents may look like.
Figure 1.4. Common Alternative Alkyl Substituents
The bond on the right side of each substituent connects to the parent molecule.If there are multiple substituents of the same type, we use the prefixes di–, tri–, tetra–, and so on to
indicate this fact. These prefixes are included directly before the substituent’s name.
4. Assign a Number to Each Substituent
Pair the substituents that you have named to the corresponding numbers in the parent chain.
Multiple substituents of the same type will get both the di–, tri–, and tetra– prefixes that we have
previously noted and also a carbon number designation—even if they are on the same carbon.
5. Complete the Name
Names always begin with the names of the substituents in alphabetical order, with each substituent
preceded by its number. Note, however, that prefixes like di–, tri–, and tetra– as well as the
hyphenated prefixes like n– and tert– (or t–) are ignored while alphabetizing. Nonhyphenated roots
that are part of the name, however, are included; these are modifiers like iso–, neo–, or cyclo–.
Then, the numbers are separated from each other with commas, and from words with hyphens.
Finally, we finish the name with the name of the backbone chain, including the suffix for the
functional group of highest priority. Figure 1.5 shows an example of an entire hydrocarbon named
with IUPAC nomenclature.